Erik Pieters of Stoke City and Wilfried Zaha of Crystal Palace compete for the ball during the Barclays Premier League match between Stoke City and Crystal Palace at the Britannia Stadium in Stoke on Trent, Englandgetty

Stoke City defender Erik Pieters has warned Louis van Gaal that he has not forgotten what the Dutchman had told him before his move from PSV Eindhoven in 2013. The Potters take on Manchester United at the Britannia Stadium on Boxing Day in a must-win game for Van Gaal, with the Red Devils having gone six games without a win in all competitions.

The Untied manager has to turn things around or face the sack, with the departure of Jose Mourinho putting the cat among the pigeons for managers who are not performing up to potential. There has been talk of Mourinho replacing the Dutchman at Old Trafford, but the former Chelsea man's agent Jorge Mendes has confirmed that there has been no official approach from the 20-time English Champions for his services.

Stoke will be a difficult proposition for United, who have lost in each of their last two games against newly promoted opposition, namely Bournemouth and Norwich City, while the Potters have hit a good run of form, annihilating Manchester City in a recent game at home. Pieters will be desperate to get the record straight with the former Netherlands manager, who had underestimated his move to the Premier League, something which may now come to haunt him.

"I remember what he said," Pieters told the Stoke Sentinel. "People still think that Stoke will be relegated at the start of each season. It happened in my first season, second season and third season.

"But in the first season, we had a top-10 finish, the second season we did it again, and we are hoping we can do it three years in a row. I'm happy with my choice but I was always confident coming here was the right move. I'm happy with my move and I'm happy with how this season is going."

The Red Devils will be without a bunch of players who are out through injury, along with Bastian Schweinsteiger, who is serving a three-game suspension for violent conduct. However, the main objective for Van Gaal will be to get his frontmen firing in front of goal, who have been extremely profligate in that department.